The contest

I would do...

panel rads w/ TRv's on each rad. home run pex to each rad off a manifold then set the boiler to run off constant circulation... voila each rad is a zone.

New system recommendation

 Spend wisely on a nice condensing boiler like a Viessmann or Triangle Tube. Don't buy a cheapie, you'll regret it. While I like Viessmann, the Triangle Tube have decent controls built in, without the need for external controls. Then again with some of the Tekmar products out there you can set yourself up with nice control strategy. Remember, outdoor reset is the key!

 Next I would put in a indirect fired water heater. Forget the "on demand" tankless water heater. While it is nice in most residential applications, you will have a high efficient heating plant that should be well equipped to provide with high efficient hot water as well.  

It's too bad that none of the underside of the floors are accessible, because some some floor warming on the common areas would be great and it would allow you to run lower temperatures through your boiler which will keep your efficiency up. Then run individual lines in a homerun type of distribution to each bedroom and put TRV's on each rad.

 Since radiant is out of the question, I would pipe a zone that would contain the dining, kitchen and living and entry and have it operated by a centrally located thermostat.The master suite could utilize this same piping loop, but be zoned with its own thermostat as well The bedrooms and bathroom would be piped in a homerun type of distribution from a common manifold . The bathroom could be off this manifold as well and could also contain a nice towel warmer Each of these rads would have the TRV on them for individual control.

Cost will end up being your enemy and you'll most likely have to sacrifice on one or more of your criteria. If it were me doing the same thing (which I am considering converting my house from forced air *cough* *cough* to radiant) I would like to think that replacing some sheetrock  and running some pex tubing would untimately be cheaper than buying a house full of panel rads. It would also be more aesthetically pleasing than baseboard convectors (pardon while I puke). In the long run, you'll be happier because your system will be comfortable and effiecient.

Good Luck!!

If radiant is out of the question, ...

Bear in mind that I am not a heating contractor.



If you are not going to use radiant heating, it will be difficult (not impossible) to get a mod|con to condense unless the design is made correctly. If you are going to use baseboard fin-tube to deliver the heat, be sure to install lots more than usual, so you can use much lower hot water temperatures than the usual 180F, because you will probably not get 60F to 80F heat loss through them.



In my house, downstairs is radiant heat in on-grade slab, so that is done by radiant, with water temperatures varying between 75F and 120 F at the exit from the boiler, and slightly less on the returns, depending on what the outdoor reset is up to. Upstairs had little "radiators" with 3 feet of fin-tube. With the previous one-zone boiler, upstairs was always cold in winter because it got the same temperature water as downstairs. The heat load is not all that great (about 6500 BTU/hr) at 0F outside, but the design day is only 14F. I figured out that 14 feet of Slant/Fin in each of the upstairs rooms would permit much lower temperature water to be supplied upstairs. Currently that is set to run from 110F to 135F supply temperatures and slightly less on the return. If I had room for more Slant/Fin, I could have arranged for even lower water temperatures up there. (That 110F could be lowered, but the heat loss upstairs is so low that the boiler rapid-cycles on warm days because the boiler cannot modulate low enough.)



With this setup it condenses almost all the time. Even the indirect-fired hot water heater condenses a lot as I have the supply to it set at 165F instead of the factory-recommended 190F. It is not affected by the outdoor reset, but it takes a while to get the return up to maximum temperature, so some condensation takes place even for that, but not as much. Since there is only one of me, and I am not a teenage girl, the hot water demand here is not great. If I had higher hot water demand, I would have to raise the supply temperature to the indirect to closer to what the manufacturer recommends.



I am a bit concerned about the cathedral ceiling room. There, radiant heating would be beneficial. Perhaps, when you say radiant is out of the question, you mean that you do not wish to dig up the floor, or alter the ceiling. But for such a room, perhaps radiant panels on the walls could be considered. The lower temperatures would reduce the stratification with the heat otherwise going up to the ceilings, leaving the inhabited parts of the room cold.

Make it GREEN....

Reduce, Reuse, and recycle.



You have a distribution system already intact. Convert it to a one pipe hot water system using drop in venturi's (Nibco) and put your panel rads on the mains.



Being a big proponent of large delta T systems, properly designed and sized, you should be able to extract enough heat to get a 30 to 40 degree delta T off that design, no problemo. Use a DCECM pump for distribution, ODR on the boiler and let 'er rip.



As for DHW, I am currently running an MC80 boiler, and am using a reverse indirect, and have NEVER run out of water. Back to back to back to back loads, are not a problem. Parallel loads are a problem. It just takes planning. (Occasionally heard from the shower "SHUT THAT %$#&^*^ DISHWASHER/CLOTHES WASHER OFF!!!)



Don't forget to take into consideration the drop in fluid temperature as it works its way through the radiators. Put the highest load on the front of the zones, and lowest loads on the back and you should be golden.



BTW, I have a one pipe system in my home, and I LOVE it. Sweet and simple.



Also, not sure how you are going to train those radiators to NOT put out any radiant heat, seeings as how that is not in your budget ;-)



Maybe you should consider just using fan coil units, and then purchase your family members some of those Bose Noise Cancelling head phones. That way you wouldn't have to deal with any radiant heat. (just busting your chops Chris:-))



Good luck on your project.



ME

The Rads

I'd be using wall panel rads with TRVS and oversize the radiators by 30-35% so max water temp is 140 on the coldest day of the year. Most panel rad tech manuals have the sizing charts so you can reduce water temps and make them most efficient with a mod-con.  I prefer to use a slightly larger boiler when using the 79g tank, but the 19 will work...expect slower recovery of the tank. If you size the rads to the "normal" 180 degree curve, you'll miss out on the mod-con's efficeny at lower temps.

new system

if going to use copper baseboard look at smiths environmental heating edge copper baseboard. can design it so system runs at 130* or 140* F on design day. this way boiler always condensing. how many people in family how many bathrooms. use alsons 1.6 gpm shower heads take out older 2.5 gpm shower heads. using less water in your showers will make your domestic hot water last longer. you said you are putting the boiler and indirect in the garage and you are going to heat the garage to 50* F how about putting a 40, 80, or 120 gallon fiberglass storage tank in garage before the indirect water heater with one or two old large cast iron radiators next to the holding tank so in the winter when cold water comes into fiberglass tank and with radiators nice and warm to heat the garage the water in fiberglass tank will warm up before going into your indirect water heater. same thing in the summer when garage is already warm. Just a thought.